mm/rmap: Convert try_to_unmap() to take a folio

Change all three callers and the worker function try_to_unmap_one().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Author: Matthew Wilcox (Oracle)

include/linux/rmap.h

@@ -194,7 +194,7 @@ int folio_referenced(struct folio *, int is_locked,
 			struct mem_cgroup *memcg, unsigned long *vm_flags);
 
 void try_to_migrate(struct page *page, enum ttu_flags flags);
-void try_to_unmap(struct page *, enum ttu_flags flags);
+void try_to_unmap(struct folio *, enum ttu_flags flags);
 
 int make_device_exclusive_range(struct mm_struct *mm, unsigned long start,
 				unsigned long end, struct page **pages,
@@ -309,7 +309,7 @@ static inline int folio_referenced(struct folio *folio, int is_locked,
 	return 0;
 }
 
-static inline void try_to_unmap(struct page *page, enum ttu_flags flags)
+static inline void try_to_unmap(struct folio *folio, enum ttu_flags flags)
 {
 }
 

mm/huge_memory.c

@@ -2251,6 +2251,7 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
 
 static void unmap_page(struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD |
 		TTU_SYNC;
 
@@ -2264,7 +2265,7 @@ static void unmap_page(struct page *page)
 	if (PageAnon(page))
 		try_to_migrate(page, ttu_flags);
 	else
-		try_to_unmap(page, ttu_flags | TTU_IGNORE_MLOCK);
+		try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK);
 
 	VM_WARN_ON_ONCE_PAGE(page_mapped(page), page);
 }

mm/khugepaged.c

@@ -1834,7 +1834,8 @@ static void collapse_file(struct mm_struct *mm,
 		}
 
 		if (page_mapped(page))
-			try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_BATCH_FLUSH);
+			try_to_unmap(page_folio(page),
+					TTU_IGNORE_MLOCK | TTU_BATCH_FLUSH);
 
 		xas_lock_irq(&xas);
 		xas_set(&xas, index);

mm/memory-failure.c

@@ -1347,6 +1347,7 @@ static int get_hwpoison_page(struct page *p, unsigned long flags)
 static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 				  int flags, struct page *hpage)
 {
+	struct folio *folio = page_folio(hpage);
 	enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC;
 	struct address_space *mapping;
 	LIST_HEAD(tokill);
@@ -1412,7 +1413,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 		collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);
 
 	if (!PageHuge(hpage)) {
-		try_to_unmap(hpage, ttu);
+		try_to_unmap(folio, ttu);
 	} else {
 		if (!PageAnon(hpage)) {
 			/*
@@ -1424,12 +1425,12 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 			 */
 			mapping = hugetlb_page_mapping_lock_write(hpage);
 			if (mapping) {
-				try_to_unmap(hpage, ttu|TTU_RMAP_LOCKED);
+				try_to_unmap(folio, ttu|TTU_RMAP_LOCKED);
 				i_mmap_unlock_write(mapping);
 			} else
 				pr_info("Memory failure: %#lx: could not lock mapping for mapped huge page\n", pfn);
 		} else {
-			try_to_unmap(hpage, ttu);
+			try_to_unmap(folio, ttu);
 		}
 	}
 

mm/memory_hotplug.c

@@ -1690,10 +1690,13 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 				      DEFAULT_RATELIMIT_BURST);
 
 	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+		struct folio *folio;
+
 		if (!pfn_valid(pfn))
 			continue;
 		page = pfn_to_page(pfn);
-		head = compound_head(page);
+		folio = page_folio(page);
+		head = &folio->page;
 
 		if (PageHuge(page)) {
 			pfn = page_to_pfn(head) + compound_nr(head) - 1;
@@ -1710,10 +1713,10 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		 * the unmap as the catch all safety net).
 		 */
 		if (PageHWPoison(page)) {
-			if (WARN_ON(PageLRU(page)))
-				isolate_lru_page(page);
-			if (page_mapped(page))
-				try_to_unmap(page, TTU_IGNORE_MLOCK);
+			if (WARN_ON(folio_test_lru(folio)))
+				folio_isolate_lru(folio);
+			if (folio_mapped(folio))
+				try_to_unmap(folio, TTU_IGNORE_MLOCK);
 			continue;
 		}
 

mm/rmap.c

@@ -1412,7 +1412,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 {
 	struct folio *folio = page_folio(page);
 	struct mm_struct *mm = vma->vm_mm;
-	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
+	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0);
 	pte_t pteval;
 	struct page *subpage;
 	bool ret = true;
@@ -1436,13 +1436,13 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 	 * For hugetlb, it could be much worse if we need to do pud
 	 * invalidation in the case of pmd sharing.
 	 *
-	 * Note that the page can not be free in this function as call of
-	 * try_to_unmap() must hold a reference on the page.
+	 * Note that the folio can not be freed in this function as call of
+	 * try_to_unmap() must hold a reference on the folio.
 	 */
 	range.end = vma_address_end(&pvmw);
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
 				address, range.end);
-	if (PageHuge(page)) {
+	if (folio_test_hugetlb(folio)) {
 		/*
 		 * If sharing is possible, start and end will be adjusted
 		 * accordingly.
@@ -1454,24 +1454,25 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 
 	while (page_vma_mapped_walk(&pvmw)) {
 		/* Unexpected PMD-mapped THP? */
-		VM_BUG_ON_PAGE(!pvmw.pte, page);
+		VM_BUG_ON_FOLIO(!pvmw.pte, folio);
 
 		/*
-		 * If the page is in an mlock()d vma, we must not swap it out.
+		 * If the folio is in an mlock()d vma, we must not swap it out.
 		 */
 		if (!(flags & TTU_IGNORE_MLOCK) &&
 		    (vma->vm_flags & VM_LOCKED)) {
 			/* Restore the mlock which got missed */
-			mlock_vma_page(page, vma, false);
+			mlock_vma_folio(folio, vma, false);
 			page_vma_mapped_walk_done(&pvmw);
 			ret = false;
 			break;
 		}
 
-		subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte);
+		subpage = folio_page(folio,
+					pte_pfn(*pvmw.pte) - folio_pfn(folio));
 		address = pvmw.address;
 
-		if (PageHuge(page) && !PageAnon(page)) {
+		if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) {
 			/*
 			 * To call huge_pmd_unshare, i_mmap_rwsem must be
 			 * held in write mode.  Caller needs to explicitly
@@ -1510,7 +1511,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		if (should_defer_flush(mm, flags)) {
 			/*
 			 * We clear the PTE but do not flush so potentially
-			 * a remote CPU could still be writing to the page.
+			 * a remote CPU could still be writing to the folio.
 			 * If the entry was previously clean then the
 			 * architecture must guarantee that a clear->dirty
 			 * transition on a cached TLB entry is written through
@@ -1523,22 +1524,22 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			pteval = ptep_clear_flush(vma, address, pvmw.pte);
 		}
 
-		/* Move the dirty bit to the page. Now the pte is gone. */
+		/* Set the dirty flag on the folio now the pte is gone. */
 		if (pte_dirty(pteval))
-			set_page_dirty(page);
+			folio_mark_dirty(folio);
 
 		/* Update high watermark before we lower rss */
 		update_hiwater_rss(mm);
 
-		if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
+		if (PageHWPoison(subpage) && !(flags & TTU_IGNORE_HWPOISON)) {
 			pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
-			if (PageHuge(page)) {
-				hugetlb_count_sub(compound_nr(page), mm);
+			if (folio_test_hugetlb(folio)) {
+				hugetlb_count_sub(folio_nr_pages(folio), mm);
 				set_huge_swap_pte_at(mm, address,
 						     pvmw.pte, pteval,
 						     vma_mmu_pagesize(vma));
 			} else {
-				dec_mm_counter(mm, mm_counter(page));
+				dec_mm_counter(mm, mm_counter(&folio->page));
 				set_pte_at(mm, address, pvmw.pte, pteval);
 			}
 
@@ -1553,18 +1554,19 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			 * migration) will not expect userfaults on already
 			 * copied pages.
 			 */
-			dec_mm_counter(mm, mm_counter(page));
+			dec_mm_counter(mm, mm_counter(&folio->page));
 			/* We have to invalidate as we cleared the pte */
 			mmu_notifier_invalidate_range(mm, address,
 						      address + PAGE_SIZE);
-		} else if (PageAnon(page)) {
+		} else if (folio_test_anon(folio)) {
 			swp_entry_t entry = { .val = page_private(subpage) };
 			pte_t swp_pte;
 			/*
 			 * Store the swap location in the pte.
 			 * See handle_pte_fault() ...
 			 */
-			if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) {
+			if (unlikely(folio_test_swapbacked(folio) !=
+					folio_test_swapcache(folio))) {
 				WARN_ON_ONCE(1);
 				ret = false;
 				/* We have to invalidate as we cleared the pte */
@@ -1575,8 +1577,8 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			}
 
 			/* MADV_FREE page check */
-			if (!PageSwapBacked(page)) {
-				if (!PageDirty(page)) {
+			if (!folio_test_swapbacked(folio)) {
+				if (!folio_test_dirty(folio)) {
 					/* Invalidate as we cleared the pte */
 					mmu_notifier_invalidate_range(mm,
 						address, address + PAGE_SIZE);
@@ -1585,11 +1587,11 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 				}
 
 				/*
-				 * If the page was redirtied, it cannot be
+				 * If the folio was redirtied, it cannot be
 				 * discarded. Remap the page to page table.
 				 */
 				set_pte_at(mm, address, pvmw.pte, pteval);
-				SetPageSwapBacked(page);
+				folio_set_swapbacked(folio);
 				ret = false;
 				page_vma_mapped_walk_done(&pvmw);
 				break;
@@ -1626,16 +1628,17 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 						      address + PAGE_SIZE);
 		} else {
 			/*
-			 * This is a locked file-backed page, thus it cannot
-			 * be removed from the page cache and replaced by a new
-			 * page before mmu_notifier_invalidate_range_end, so no
-			 * concurrent thread might update its page table to
-			 * point at new page while a device still is using this
-			 * page.
+			 * This is a locked file-backed folio,
+			 * so it cannot be removed from the page
+			 * cache and replaced by a new folio before
+			 * mmu_notifier_invalidate_range_end, so no
+			 * concurrent thread might update its page table
+			 * to point at a new folio while a device is
+			 * still using this folio.
 			 *
 			 * See Documentation/vm/mmu_notifier.rst
 			 */
-			dec_mm_counter(mm, mm_counter_file(page));
+			dec_mm_counter(mm, mm_counter_file(&folio->page));
 		}
 discard:
 		/*
@@ -1645,10 +1648,10 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		 *
 		 * See Documentation/vm/mmu_notifier.rst
 		 */
-		page_remove_rmap(subpage, vma, PageHuge(page));
+		page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
 		if (vma->vm_flags & VM_LOCKED)
 			mlock_page_drain(smp_processor_id());
-		put_page(page);
+		folio_put(folio);
 	}
 
 	mmu_notifier_invalidate_range_end(&range);
@@ -1667,17 +1670,17 @@ static int page_not_mapped(struct page *page)
 }
 
 /**
- * try_to_unmap - try to remove all page table mappings to a page
- * @page: the page to get unmapped
+ * try_to_unmap - Try to remove all page table mappings to a folio.
+ * @folio: The folio to unmap.
  * @flags: action and flags
  *
  * Tries to remove all the page table entries which are mapping this
- * page, used in the pageout path.  Caller must hold the page lock.
+ * folio.  It is the caller's responsibility to check if the folio is
+ * still mapped if needed (use TTU_SYNC to prevent accounting races).
  *
- * It is the caller's responsibility to check if the page is still
- * mapped when needed (use TTU_SYNC to prevent accounting races).
+ * Context: Caller must hold the folio lock.
  */
-void try_to_unmap(struct page *page, enum ttu_flags flags)
+void try_to_unmap(struct folio *folio, enum ttu_flags flags)
 {
 	struct rmap_walk_control rwc = {
 		.rmap_one = try_to_unmap_one,
@@ -1687,9 +1690,9 @@ void try_to_unmap(struct page *page, enum ttu_flags flags)
 	};
 
 	if (flags & TTU_RMAP_LOCKED)
-		rmap_walk_locked(page, &rwc);
+		rmap_walk_locked(&folio->page, &rwc);
 	else
-		rmap_walk(page, &rwc);
+		rmap_walk(&folio->page, &rwc);
 }
 
 /*

mm/vmscan.c

@@ -1768,7 +1768,7 @@ static unsigned int shrink_page_list(struct list_head *page_list,
 			if (unlikely(PageTransHuge(page)))
 				flags |= TTU_SPLIT_HUGE_PMD;
 
-			try_to_unmap(page, flags);
+			try_to_unmap(folio, flags);
 			if (page_mapped(page)) {
 				stat->nr_unmap_fail += nr_pages;
 				if (!was_swapbacked && PageSwapBacked(page))